The present invention relates to apparatus for measuring blood pressure.
Hitherto, blood pressure has been measured by providing an inflatable cuff which is wrapped around the upper arm, and inflated. The pressure within the cuff is monitored by means of a mercury manometer.
In use, the device is wrapped around the upper arm of a patient and a pulse is detected using a stethoscope usually from the artery in the elbow. The cuff is inflated until the pulse is no longer audible and then the pressure is slowly released and the pressure at which the pulse just becomes discernable is noted. This is known as the systolic blood pressure. The pressure is further released progressively until the audibility of the pulse changes and the effect of the pulse becomes more muffled. The pressure at which this occurs is known as the diastolic blood pressure.
In order to determine a person's blood pressure, it has always been thought necessary to take both the systolic and the diastolic pressures. Recent research, however, has indicated that probably the more important pressure measurement is the systolic pressure, that is to say, the highest pressure to which blood is subjected.
Furthermore, existing methods of taking blood pressure usually require a patient, at least to a limited extent, to undress to reveal the upper arm and secondly, requires a second person to manipulate a stethoscope in order to detect the pulse and changes in pulse necessary to record the pressures concerned.
Accordingly, there is a major need for a method of measuring blood pressure which does not require the patient to undress and which can be self-administered.